Looking for a Denver machine shop that excels at Inconel machining?
At Focused on Machining, we love working with challenging materials that many other job shops try to avoid. Titanium and Nitronic 60 are examples of materials that get us excited to come to work every morning, but one material that’s hard to top is Inconel.
Known for its exceptional resistance to corrosion and high temperatures as well as its superior pressure tolerance, Inconel is an ideal material for aerospace machining. It doesn’t move or expand with the introduction of extreme heat, which is why you’ll often see it used for jet engine components.
But the same properties that make Inconel such a desirable material also make it extremely difficult to machine. Like titanium, Inconel is prone to work hardening, which increases the risks of tool wearing and potentially compromises part quality.
Today, we’ll review some of the most common grades of Inconel and explore why Focused on Machining is your go-to shop for Inconel machining.
Common Grades of Inconel
There are more than 20 metal alloys in the Inconel family, but here are several of the most common ones:
Inconel 600. This versatile engineering material has exceptional heat-resistant and corrosion-resistant properties. From a mechanical standpoint, it combines both high strength and excellent workability. It’s capable of withstanding temperatures ranging from cryogenic to above 2,000 degrees Fahrenheit. Inconel 600 is ideal for pharmaceutical applications (bubble towers, heaters, stills), nuclear reactors, and engine and airframe components.
Inconel 617. This grade of Inconel is known for its high-temperature strength, oxidation resistance, and corrosion resistance. Inconel 617 is common in gas turbine components like transition liners, combustion cans, and ducting due to its ability to maintain high strength and oxidation resistance at temperatures exceeding 1,800 degrees Fahrenheit.
Inconel 625. The unique combination of chemical elements in Inconel 625 yields high strength and superior corrosion-resistant properties in temperatures ranging from cryogenic to 1,800 degrees Fahrenheit. This grade of Inconel is a great choice for applications like reaction vessels, tubing, and heat exchangers that need to be strong and capable of withstanding corrosive environments.
Inconel 690. With its high level of chromium, Inconel 690 can successfully resist oxidizing chemicals and high-temperature oxidizing gases. The substantial nickel content ensures exceptional resistance to stress-corrosion cracking, enabling it to hold up well to chloride and sodium hydroxide. Inconel 690 is common in applications where nitric acid and nitric/hydrofluoric acid are present, such as tail-gas reheaters and heating coils. It’s also ideal for applications that process sulfuric acid.
Inconel 718. This age-hardenable alloy has high strength and corrosion-resistant properties and can withstand temperatures ranging from -423 degrees Fahrenheit to 1,300 degrees Fahrenheit. From a manufacturing standpoint, Inconel 718 is known for being relatively easy to work with and even stands up exceptionally well to welding. It’s the preferred Inconel grade for various applications, including components for gas turbine engines, fasteners, and instrumentation parts.
Inconel X-750. This precipitation-hardenable grade of Inconel possesses high strength, oxidation resistance, and corrosion resistance at temperatures ranging from cryogenic to 1,300 degrees Fahrenheit. It maintains exceptional strength up to 1,800 degrees Fahrenheit with heat treating. Inconel X-750 is common in applications such as gas turbines, rocket engine thrust chambers, airframes, extrusion dies, forming tools, springs, and fasteners.
Inconel Machining at Focused on Machining
When you need Inconel machining for your aerospace applications, you need an AS9100 machine shop like Focused on Machining that does what it takes to crack the code on challenging materials.
In recent years, 3D printing has become increasingly popular for Inconel parts with complex geometries, such as a design requiring internal cooling channels. While this is an ideal use case for 3D printing, precision machining remains the optimal choice for simpler components. For instance, when manufacturing parts such as plugs, bushings, or washers that require tight tolerances, machining is often more efficient than 3D printing.
In addition, machining can often be faster for many parts than 3D printing. While 3D printing can produce parts quickly, the required post-processing steps often significantly increase lead times. Machining, by contrast, often provides a more direct path to a finished part, resulting in overall faster delivery times.
Many of the Inconel alloys we work with have gone through an annealing process that alters the material properties to increase ductility and reduce hardness. In these cases, we can use our standard tooling and the special tooling we already have on hand for hard materials while carefully monitoring feeds and speeds during machining. However, if we’re cutting heat-treated Inconel, we need to use custom ceramic tooling that won’t break easily.
We typically passivate Inconel parts post-machining to remove iron and other impurities from the surface and produce a protective oxide coating that further resists corrosion.
We’re thrilled to be working on some exciting Inconel parts right now and can’t wait to take on more of these projects. Request a quote for Inconel machining today!
Frequently Asked Questions
Is Inconel difficult to machine?
Inconel is challenging to machine due to its work hardening, high cutting forces, heat generation, and susceptibility to workpiece deflection, leading to tool wear and dimensional inaccuracies.
Does Inconel 718 rust?
Inconel 718 resists corrosion in seawater but may corrode in extreme marine conditions like high salinity, elevated temperatures, and high chloride levels
Is Inconel stronger than titanium?
Both Inconel and titanium are very strong, but titanium is generally considered stronger, especially at high temperatures. Titanium is also much lighter than Inconel, making it a better choice for weight-sensitive applications, such as in the aerospace industry.
Why is Inconel so expensive?
Inconel is expensive due to its high nickel and chromium content, both costly metals. Its premium alloy properties, including excellent corrosion resistance and high-temperature tolerance, justify the price for demanding applications. Nickel supply fluctuations can also impact its cost.